1. Field of the Invention
This invention relates to a preparation for pretreating or steeping stubbornly soiled dishes and a process for washing such dishes therewith.
2. Discussion of Related Art
It is known that dishwashing machines use alkaline detergent mixtures which consist essentially of inorganic salts, such as alkali metal phosphates, alkali metal silicates and alkali metal carbonates, and active chlorine donors and which optionally contain small additions of a low-foam nonionic surfactant to improve wetting. Detergent mixtures such as these generally show good detergency with respect to soil of all kinds at normal washing temperatures of from 55.degree. C. to 65.degree. C. However, difficulties are encountered in the dishwashing process when the soil to be removed consists of burnt-on or dried-out, protein- and/or starch-containing food remains and white or grey coatings on the items to be washed which are largely attributable to alkaline-insoluble, inorganic calcium salts and which emanate on the one hand from the foods themselves and, on the other hand, from the water used in the preparation thereof. These soil types are not always completely removed in the dishwashing process, resulting in complaints on the part of the user or causing the user not to wash these items in the machine.
Accordingly, an object of the present invention is to provide a pretreatment or steeping preparation which is easy to use and which leads to the complete removal of problem soils in automatic dishwashing machines. Although U.S. Pat. No. 4,116,851 describes pasty, thixotropic, highly alkaline pot-cleaning detergents which contain various thickeners and active chlorine compounds and which, for practical application, are applied to the items to be washed and are submerged in water, remaining at the point of contact for a relatively long time by virtue of their gel structure so that they have a particularly long-lasting effect, there is nothing in said patent to suggest that preparations of the type described in the present invention would be suitable for use as a pretreatment or steeping preparation in dishwashing machines.
On the one hand, the contact time of the subject preparation should be kept as short as possible in order to not delay work programs. However, even if on the other hand, the items to be washed after treatment with the preparation have to stand for relatively long periods of time during collection in the dishwashing machine, food remains should be prevented from drying out again together with the preparation. The preparation according to the invention should be used by the user bringing the stubborn food remains, for example in a cooking pot or a frying pan, into contact with the preparation, for example by spray pumps, brushes, foam guns, aerosol cans, then immediately placing the items to be washed in the best position in the washing machine, i.e. with the pot opening facing downwards towards the water jet, most of the viscous product adhering to the surface of the pot, and starting the dishwashing program as required. There should be no need for the pretreatment or steeping preparation to be rinsed out before the dishwashing process.